These are nice, beefy knurled knobs with a full 20mm diameter. They come complete with a removable insert that allows you to use them on either metric, US, or solid shaft pots. All Q-Parts knobs utilize a set screw to insure a tight, non-wobbly...

Here's a whole guitar product category devoted to the less expensive imported guitars. These guitar parts are all metric in dimension, which assures a much easier fit for replacement part purposes on imported guitars.